Wal-Mart Stores Inc. is a giant no doubt, but arguably one of the most nimble when it comes to handling weather-related disasters for its workforce and its 140 million weekly customers.

Tucked inside a nondescript building at Eighth and Walton in Bentonville, teams from logistics, merchandising, safety and security, human resources, Sam’s Club, store operations and other emergency responders worked through the weekend to make sure the 900 stores in the path of Hurricane Sandy could stay open as long as needed. And then re-open as quickly as possible once cleared to do so by federal and state emergency management

As of mid-afternoon Monday (Oct. 29) the retail giant had closed 143 stores from North Carolina to Massachusetts.

Mark Cooper, senior director of the Global Emergency Management for Wal-Mart, said the retailer is operating on a level-three activation giving 24-hour support to the stores and associates out in the affected communities.

Emergency replenishment is crucial, Cooper said, with workers in Bentonville making calls twice a day with operators in the field to make sure they have all the necessary supplies and merchandise.

“We have several distribution centers designated to help with disaster relief, they are overstocked with the items most often requested,” Cooper said.

What makes this storm different are the winter element of the nor’easter and the shear scale of its size and potential impact, he said. Elizabeth Carr, manager of associate relations for Wal-Mart, said more than 400 local volunteers are manning the phone call center at the home office for associates out in the field.

“The volunteers are all home office associates who began working the phones yesterday. We expect 250,000 of our associates in 900 stores could be impacted from this storm. One of the things we offer is displacement assistance if they have to be evacuated from their homes. We also give them shelter information and help them stay connected with their family members,” Carr said.

The scope of Sandy is more than four times larger for Wal-Mart than Hurricane Isaac was in August. There were 100 stores and 6,000 associates in the path of Isaac, according to Carr.

She said the call center answers associate questions as simple as if certain stores are open, to coordinating rescues, if necessary, with emergency evacuation crews. Wal-Mart also allows workers to pick up shifts at other open stores in case of store closures.

Wal-Mart did not give estimates on store traffic over the weekend or discuss the potential financial impact – good or bad.

Ryan Sweet, a senior economist at Moody’s Analytics, says Sandy will be a costly storm but one that would have little impact on fourth quarter gross domestic product. Sweet estimates the lost economic output between Washington, D.C. and New York City would equal at least $10 billion a day.

Other economists say Sandy could boost spending for essentials, and rob from discretionary ticket sales in the weeks ahead.

Early estimates for loss of sales from retailers, restaurants and grocers that must close for the storm is less than 1%, according to Streettalk Advisors.

Costco co-founder Jim Sinegal said on CNBC Monday morning, the company’s Bridgewater, N.J., store did $900,000 in sales on Friday alone, the kind of volume hit only on Black Friday.

He, like Wal-Mart, said the distribution centers have been stocked heavily to ensure the stores get merchandise replenished as quickly as possible for the customers in need.

Lowe’s has about 200 stores located in Sandy’s path, and the company estimated 50 to 60 store closings later Monday (Oct. 29).

Terry Johnson, senior vice president of store operations, says there are no trucks moving into the most seriously affected areas at this point. But they are sitting ready to pull out once given the word from emergency management.